Application of Cochlear Implant for Two Cases of Maternally Inherited Diabetes and Deafness

Abstract

Maternally inherited diabetes and deafness (MIDD) is a rare subtype form of diabetes caused by a mitochondrial DNA defect associated with m.3243A>G mutation. More than 90% of MIDD cases suffer from bilateral progressive sensorineural hearing loss. Here, we report two cases of MIDD with bilateral profound hearing loss that were successfully treated with cochlear implantation. Case 1 was a 61-year-old man who complained of bilateral progressive hearing loss since the age of 40 years old and who visited our department seeking treatment. He was diagnosed as having MIDD based on a genetic analysis of mitochondrial DNA that revealed a 3243 A to G substitution. Cochlear implantation (CI) was performed for the right ear, which exhibited profound hearing loss. At 5 years after the CI, the patient had acquired hearing function enabling more than 90% of spoken words to be discriminated. Case 2 was a 44-year-old woman who had suffered from diabetes and deafness since the age of 24 years and who had a 3243 A to G substitution in her mitochondrial DNA. She visited our department for cochlear implantation because hearing aids had never improved her hearing. At 6 years after the CI, she had acquired good speech discrimination. We suggest that CI might be a useful treatment for profound hearing loss in patients with MIDD.